Definitely a good episode, but the triumvirate of Madam Vastra, Jenny and Strax have always delivered. Strax, and even Jenny to an extent in this episode, often manage to exceed their nominal employer, Madam Vastra! Apparently we'll see them again later in this series, which is good.
The Tom-Tom reference was a mild joke, although it was clear from the moment he comes out with his directions that this was going to relate to car GPS units. I'm not sure it was worth the contrived effort to insert it into the episode however, but it doesn't distract significantly.
It hadn't occurred to me, that Jenny in her catsuit, which we've seen before in A Good Man Goes to War, was a nod to Diana Rigg and The Avengers, but I'd imagine that it was a deliberate homage in this episode. She certainly had a quick session of beating up the baddies, but realistically it didn't continue to the extremes that is often shown, with her attempting to fight a huge crowd of armed nasties, and instead they followed the Doctor's traditional maxim of running.
In some respects, there wasn't much of a story, but it had so many good little bits in it, that I'm not too fussed!